Carbon dioxide (CO2) emissions from naturally wet and drained nutrient-rich organic forests soils

Abstract

Implementation of climate change mitigation measures in forestry has a key role to successfully fulfil the climate change policy goals of Land use, land use change and forest sector set by the Paris Agreement to fully offset total GHG emissions in the country by CO2 removals in 2050. GHG emissions from organic soils in forest land have significant impact on total emissions of Latvia, however, high emissions also indicate the potential of climate change mitigation measures. This study aims to evaluate CO2 emissions from drained and naturally wet nutrient-rich forest soils to improve knowledge of forest management practice impact on GHG emissions. The study is conducted in 21 drained (Myrtillosa turf.mel. and Oxalidosa turf. mel.) and 10 naturally wet (Dryopterioso–caricosa and Filipendulosa) forest sites with nutrient-rich organic soils for 12 consecutive months. Soil total CO2 emissions were measured by closed manual non-transparent chamber method. The groundwater level, soil and air temperature were measured to evaluate factors affecting CO2 emission. Empirical data collected within the scope of the study showed high correlation (r = 0.85) between CO2 emissions and temperature, however, the groundwater level depth had no considerable impact on emissions. Total soil CO2 emissions from drained nutrient-rich organic soils ranged from 5.44 t ± 0.1 tC·ha·yr in black alder stands to 9.76 ± 2.47 tC·ha·yr in clearcut areas (average 7.35 ± 0.89 tC·ha·yr), while CO2 emissions from forest sites with naturally wet soil ranged from 5.73 ± 2.23 tC·ha·yr in spruce stands to 10.41 ± 4.33 tC·ha·yr in clearcut areas (average 7.02 ± 0.96 tC·ha·yr). The study results demonstrate that drainage does not have significant effect on CO2 emissions.